Document Content

THE GOVERNMENT

THE GOVERNMENT

DECREE No. 65/2001/ND-CP OF SEPTEMBER 28, 2001 PROMULGATING THE LEGITIMATE MEASUREMENT UNIT SYSTEM OF THE SOCIALIST REPUBLIC OF VIETNAM

THE GOVERNMENT

Pursuant to the September 30, 1992 Law on Organization of the Government;

Pursuant to the October 6, 1999 Ordinance on Measurement;

At the proposal of the Minister of Science, Technology and Environment,

DECREES:

Article 1.- To promulgate the lawful system of measurement units of the Socialist Republic of Vietnam, prescribed in Appendix I attached to this Decree, consisting of:

1. Units of the international system of units of measurement (SI); decimal multiples and submultiples of SI units, and other units which are used according to international practices.

2. Units consistently derived from the international system of units of measurement and units on the conventional scale used worldwide for quantities not yet prescribed in Clause 1 of this Article.

Article 2.- State agencies, economic organizations, political organizations, socio-political organizations, social organizations, socio-professional organizations, armed force units and all individuals, when using measuring equipment, presenting measurement results, expressing quantifier values in units of measurement in the economic, health and public safety, education, standardization domains and in activities of administrative character, must use legitimate units of measurement as prescribed in Article 1 of this Decree, except for the case stated in Article 3 of this Decree.

Article 3.- Where organizations and individuals carry out import/export-related activities, apart from the legitimate units of measurement, they may use other measurement units according to international maritime, aviation and railway transport treaties or agreements, which the Socialist Republic of Vietnam has acceded to or signed.

Article 4.- To facilitate the conversion of old measurement units into legitimate ones under the provisions of this Decree, organizations and individuals are allowed to use for a definite time 10 old measurement units till the end of December 31, 2005 and five old measurement units till the end of December 31, 2010 as prescribed in Appendix II to this Decree.

The ministries, branches and People�s Committees of all levels, all organizations and competent individuals shall, within the ambit of their respective functions, tasks and powers, have to make necessary preparations and conditions for shifting to the use of all lawful measurement units on the prescribed schedule.

Article 5.- This Decree replaces Decree No. 186/CP of December 26, 1964 and takes effect 15 days after its signing.

Article 6.- The ministers, the heads of the ministerial-level agencies, the heads of the agencies attached to the Government and the presidents of the People�s Committees of the provinces and centrally-run cities shall have to implement this Decree.

The Minister of Science, Technology and Environment shall organize and guide the implementation of this Decree.

On behalf of the Government

Prime Minister
PHAN VAN KHAI

APPENDIX 1

LEGITIMATE UNITS OF MEASUREMENT OF THE SOCIALIST REPUBLIC OF VIETNAM

(Issued together with the Government�s Decree No. 65/2001/ND-CP of September 28, 2001)

A. Units:

I. Units of space, time and periodic phenomena

Ordinal

Quantity

Units

Description

number

Name

Symbol

1

Length

meter

m

The meter is the length of path traveled by light in a vacuum during a time interval of 1/299 792 458 of a second (17 th CGPM*, 1983).

The base unit.

* CGPM: A French acronym for the General Conference on International Measurements and Weights.

2

Plane angle

radian

rad

The radian is a plane angle between two radii of a circle which cuts off on the circumference an arc equal in length to the radius

1 rad = 1m/1m = 1

degree

o

1o = (p /180) rad

minute

�

1� = (1/60)o = (p /10 800) rad

second

"

1" = (1/60)� = (p /648 000) rad

3

Solid angle

steradian

Sr

The steradian is a solid angle, which, having its vertex at the center of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.

1 sr = 1m2m2 /1m2 = 1

4

Area

square meter

m2

The square meter is the area of a square with 1- meter sides.

1m2 = 1m . 1m

hectare

ha

1 ha = 0.01 km2 = 104 m2

For land measurements.

5

Volume, capacity

cubic meter

m3

The cubic meter is the volume of a cube with one-meter sides

1 m3 = 1m . 1m . 1m

Having decimal multiples and submultiples in Section B.

liter

l, L

The liter is the capacity equal to one cubic decimeter

1 l = 1 dm3 = 10-3 m3

6

Time

second

s

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom the 13 th CGPM, 1967).

The base unit.

minute

min

1 min = 60 s

hour

h

1h = 60 min = 3,600 s

day

d

1d = 24 h = 86,400 s

7

Frequency

hertz

Hz

The hertz is the frequency of a periodic phenomenon occurring one cycle per second.

1 Hz = 1s-1

8

Angular velocity

radian per second

rad/s

Radian per second is the angular velocity of an object rotating steadily around a fixed axis in an angle of 1 radian in 1 second.

1rad/s = 1s-1

9

Angular acceleration

radian per second squared

rad/s2

Radian per second squared is the angular acceleration of an object with an angular velocity steadily changing one radian per second in 1 second.

1 rad/s2 = 1 s-2

10

Velocity

meter per second

m/s

Meter per second is the velocity of an object travelling 1 meter in one second.

1m/s = 1m.s-1

kilometer per hour

km/h

Kilometer per hour is the velocity of an object travelling 1,000 meters in an hour

1km/h = (1/3.6)m/s = 0.277 778 m/s

11

Acceleration

meter per second squared

m/s2

Meter per second squared is the acceleration of an object with a velocity steadily changing 1 meter per second in a second

1m/s2 = 1m.s-2

12

Level of field quantity

neper

Np

The neper is the level of a field quantity when the ratio between this quantity and a compared quantity of the same kind is equal to e

1Np = ln (F/Fo) = ln (e) = 1

bel

B

The bel is the level of a field quantity when the ratio between this quantity and a compared quantity of the same kind is equal to 101/2

1B = 2lg (F/Fo) = 2lg101/2 = 1

decibel

dB

1dB = [(ln10)/20] Np (precisely) = 0.115 129 3 Np

13

Level of power quantity

neper

Np

The neper is the level of a power quantity when the ratio between this quantity and a compared quantity of the same kind is equal to e2

1Np = (1/2) ln (P/Po) = (1/2) lne2 = 1

bel

B

The bel is the level of a power quantity when the ratio between this quantity and a compared quantity of the same kind is equal to 10

1B = lg(P/Po) = lg10 = 1

decibel

dB

1dB = [(ln10)/20] Np (precisely) = 0.115 129 3 Np

II. Mechanical units

1

Weight

kilogram

kg

The kilogram is the unit of mass, equal to the mass of the international prototype of the kilogram (third CGPM, 1901).

The base unit.

ta (quintal)

ta

1 ta = 100 kg

ton

t

1 t = 1,000 kg

Having decimal multiplies and submultiples in Section B.

2

Weight by length (length density)

kilogram per meter

kg/m

Kilogram per meter is the weight by length of a homogeneous object of even cross-section, which is 1 kilogram in weight and 1 meter in length.

1kg/m = 1kg.m-1

3

Weight by surface (surface density)

kilogram per square meter

kg/m2

Kilogram per square meter is the weight by surface of a homogeneous object of even thickness, which is 1 kilogram in weight and 1 square meter in area.

1kg/m2 = 1kg.m-2

4

Specific weight (density)

kilogram per cubic meter

kg/m3

Kilogram per cubic meter is the specific weight of a homogeneous object which is 1 kilogram in weight and 1 cubic meter in volume.

1kg/m3 = 1kg.m-3

ton per cubic meter

t/m3

Ton per cubic meter is the specific weight of a homogeneous object, which is 1 ton in weight and 1 cubic meter in volume.

1t/m3 = 103 kg/m3

kilogram per liter

kg/l, kg/L

Kilogram per liter is the specific weight of a homogeneous object, which is 1 kilogram in weight and 1 liter in volume.

1kg/l = 10-3kg/m3

5

Force

newton

N

The newton is a force which gives a mass of 1 kilogram an acceleration of 1 meter per second squared

1N = 1kg.1m/s2 = 1m.kg.s-2

6

Moment of force

Newton meter

N.m

Newton meter is the moment of a force of 1 newton to a point with a radius vector of 1 meter between that point and another point in the direction of the force.

1 N.m = 1m2.kg.s-2

7

Pressure, stress

pascal

Pa

The pascal is the pressure generated by a force of 1 newton applied perpendicularly over an area of 1 square meter

1Pa = 1N/1m2 = 1m-1.kg.s-2

bar

bar

1 bar = 100 kPa (precisely) = 0.1 MPa = 105 Pa

8

Dynamic viscosity

Pascal second

Pa.s

Pascal second is the dynamic viscosity of a homogeneous, isotropic liquid flowing in layers, when between two plane layers in parallel with the flow and 1 meter apart there is a velocity difference of 1 meter per second, and on the surface of these layers there appears a tangent stress of 1 pascal.

1Pa.s = 1Pa.1m/(1m/s) = 1m-1.kg.s-1

9

Kinetic viscosity

Square meter per second

m2/s

Square meter per second is the kinetic viscosity of a liquid having a dynamic viscosity of 1 pascal second and a specific weight of 1 kilogram per cubic meter.

1m2/s = 1Pa.s/(1kg/m3) = 1m2.s-1

10

Work, energy

joule

J

The joule is the amount of work done when the point of application of 1 newton is displaced for a distance of 1 meter in the direction of the force.

1J = 1N.1m = 1m2.kg.s-2

11

Power

watt

W

The watt is the power which gives rise to the production of energy at the rate of 1 joule per second.

1W = 1J/1s = 1m2.kg.s-1

12

Volume velocity

cubic meter per second

m3/s

Cubic meter per second is the volume velocity for a substance of 1 cubic meter in volume to cross a given cross-section in a second.

1m3/s = 1m3.s-1

13

Weight velocity

Kilogram per second

kg/s

Kilogram per second is weight velocity of a homogeneous flow for a substance of 1 kilogram in weight to cross a given section in 1 second.

1kg/s = 1kg.s-1

III. Thermal units

1

Thermo- dynamic temperature

kelvin

K

The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water (13th CGPM, 1967).

The base unit.

2

Celsius temperature

degree Celsius

oC

Degree Celsius is the specific name of kelvin to denote the values of Celsius temperature

t = T - To; in which t is Celsius temperature, T is the thermodynamic temperature and To is determined as equal to 273.15 K.

3

Energy

joule

J

1J = 1N.1m = 1m2.kg.s-2

4

Specific energy

joule per kilogram

J/kg

Joule per kilogram is the specific energy of a system of one kilogram in weight that obtains or emits an energy of 1 joule when being dissolved or completing a chemical reaction.

1J/kg = 1m2. s-2

5

Heat capacity

joule per kelvin

J/K

Joule per kelvin is the heat capacity of a system which needs an energy of 1 joule to increase its temperature one more kelvin.

1J/K = 1m2kg. S-2. .K-1

6

Specific heat capacity

joule per kilogram kelvin

J/(kg.K)

Joule per kilogram kelvin is the specific heat capacity of a homogeneous object of 1 kilogram in a constant pressure or volume, which, when an energy of 1 joule is added, will increase the temperature by 1 kelvin.

1J(kg.K) = 1m2.s-2.K-1

7

Thermal flux

watt

W

The watt is the thermal flux to carry an energy of 1 joule in a second.

1W = 1J/1s = 1m2.kg.s-3

8

Surface thermal flux (heat flux density)

watt per square meter

W/m2

Watt per square meter is the surface thermal flux when a thermal flux of 1 watt running through each square meter of the surface.

1W/m2 = 1kg.s-3

9

Thermal conductivity co-efficient

watt per square meter kelvin

W (m2.K)

Watt per square meter kelvin is the thermal conductivity co- efficient between two environments with a temperature difference of 1 kelvin and the surface thermal flux of the contact surface is 1 watt per square meter.

1W/(m2.K) = 1 kg.s-3.K-1

10

Thermal conductivity (conductivity co-efficient)

watt per meter kelvin

W/(m.K)

Watt per meter kelvin is the thermal conductivity of a homogeneous object containing a temperature difference of 1 kelvin between two parallel surfaces of 1 square meter placed 1 meter apart, which produces a thermal flux of 1 watt between these two surfaces.

1W/(m.K) = 1m.kg. s-3.K-1

11

Thermal diffusivity

square meter per second

m2/s

Square meter per second is the thermal diffusivity of an environment where the isothermal surfaces at any point of time are parallel ones and in every second the temperature at such point of time fluctuates 1 kelvin when the temperature gradient changes 1 kelvin per meter on each meter of length in the direction perpendicular to the isothermal surfaces.

1m2/s = 1m2.s-1

IV. Electric and magnetic units

1

Electric current (electric current intensity)

ampere

A

The ampere is that constant current, which, if maintained in two straight parallel conducting wires of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2. 10-7 newton per meter of length (9th CGPM, 1948).

The base unit.

2

Electric quantity

coulomb

C

The coulomb is the quantity of electricity transported in 1 second by a current of 1 ampere.

1C = 1s.A

3

Voltage, electric potential difference, electromotive force

volt

V

The volt is the difference of electric potential between two points of a conducting wire when a constant current of 1 ampere between those points dissipates a power of one watt.

1 V = 1 W/1A = 1m2.kg.s-3.A-1

4

Electric field strength

volt per meter

V/m

Volt per meter is the strength of an electric field generating a force of 1 newton on an object having an electric quantity of 1 coulomb.

1V/m = 1m.kg.s-3.A-1

5

Electric resistance

ohm

W

The ohm is the electric resistance between two points of an homogeneous conductor of the same temperature when between these two points there is an electric potential difference of one volt, which produces a constant current of 1 ampere

1 W = 1V/1A = 1m2.kg.s-3.A-2

6

Electric conductance

siemens

S

The siemens is the electric conductance of a conductor having the electric resistance of 1 ohm.

1S = 1A/1V = 1m-2.kg-1.s3.A2

7

Electric flux

coulomb

C

The coulomb is the electric flux passing through a closed surface surrounding an electric quantity of 1 coulomb.

1C = 1s.A

8

Density, electric flux

coulomb per square meter

C/m2

Coulomb per square meter is the electric flux density in a flat capacitor having two plates of infinite width, put in parallel in vacuum and each square meter of such plate is charged with an electric quantity of 1 coulomb.

1C/m2 = 1m-2.s.A

9

Work, energy

joule

J

1J = 1N.1m = 1m2.kg.s-2

watt hour

W.h

1W.h = 3.6 x 103J = 3.6 kJ

Having decimal multiplies and submultiples in Section B

electron-von

eV

The electronvon is the work done when an electric quantity equal to that of an electron passing in an electromagnetic field a distance between the two ends of which there is an electric potential difference of one volt.

1eV = 1.602 177 x 10-19 J = 160.217 7 zJ

Having decimal multiplies and submultiples in Section B

10

Magnetic field strength

ampere per meter

A/m

Ampere per meter is the magnetic field strength generated in vacuum by an electric current of 1 ampere passing through a straight conductor, of infinite length, of negligible circular cross-section, at points of a circle sharing the same axis with such conductor and having a circumference of 1 meter

1A/m = 1m-1.A

11

Electric capacitance

farad

F

The farad is the electric capacitance of a capacitor between the plates of which there appears a difference of potential of 1 volt when it is charged by an electric quantity of 1 coulomb.

1F = 1C/1V = 1m-2.kg-1.s4.A2

12

Electro- magnetic inductance

henry

H

The henry is the electromagnetic inductance of a closed circuit in which an electromotive force of 1 volt is produced when the electric current in the circuit varies uniformly at a rate of 1 ampere per second,

1H = 1V.1s/1A = 1m2.kg.s-2.A-2

13

Magnetic flux

weber

Wb

The weber is the magnetic flux, linking a circuit of one turn, produces in it an electromotive force of 1 volt as it is reduced to zero at a uniform rate in a second.

1Wb = 1V.1s = 1m2.kg.s-2.A-1

14

Magnetic flux density,

tesla

T

The tesla is the magnetic flux density in a surface of one square meter caused by a uniform magnetic flux of 1 weber perpendicular to that surface.

1T = 1Wb/1m2 = 1kg.s-2.A-1

15

Magnetomo- tive force

ampere

A

The ampere is the magnetomotive force in a closed line linking to a conductor in which a current of 1 ampere is flowing through.

1A = 1A

16

Effective power (power)

watt

W

1W = 1m2. kg.s-3

17

Apparent power

volt ampere

V.A

Volt ampere is the apparent power in a circuit section placed below an effective potential difference of 1 volt, in which a current of an effective intensity of 1 ampere is passing through.

1V.A = 1m2. kg.s-3

18

Resistance capacity

var

var

The var is the resistance capacity in a pure inductance (or pure electric capacitance) circuit section placed below an effective potential difference of 1 volt, in which a current of an effective intensity of 1 ampere is passing through.

1var = 1V.A = 1m2.kg.s-3

V. Units of light and related electro-magnetic radiation

1

Radiant energy

joule

J

1J = 1N.1m = 1m2.kg.s-2

2

Radiant capacity (radiant flux)

watt

W

1W = 1J/1s = 1m2.kg.s-3

3

Radiant intensity

watt per steradian

W/sr

Watt per steradian is the radiant intensity of a uniform point source emitting a radiant flux of 1 watt in a solid angle of 1 steradian.

1W/sr = 1m2.kg.s-3

4

Radiance

watt per square meter steradian

W/(sr.m2)

Watt per square meter steradian is the radiance in a given direction at a point above a surface a unit area of which has a radiant intensity of 1 watt per steradian and the area of the projection of such unit area on the surface perpendicular to such direction is 1 square meter.

1W/(sr.m2) = 1kg.s-3

5

Radiant capacity

watt per square meter

W/m2

Watt per square meter is the radiant capacity at a point above the surface, which radiates a radiant flux of 1 watt on 1 unit area of 1 square meter of such surface.

1W/m2 = 1 kg.s-3

6

Illumination

watt per square meter

W/m2

Watt per square meter is the illumination at a point above the surface, which radiates a radiant flux of 1 watt on 1 unit area of 1 square meter of such surface.

1W/m2 = 1 kg.s-3

7

Luminous intensity

candela

cd

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian (16th CGPM, 1979).

The base unit.

8

Luminance

candela per square meter

cd/m2

Candela per square meter is the luminance of a flat source of one square meter with a luminous intensity of one candela measured in a direction perpendicular to the source.

1cd/m2 = 1m-2.cd

9

Luminous

flux

lumen

lm

The lumen is the luminous flux emitted in a solid angle of 1 steradian by a uniform point source having an intensity of 1 candela.

1lm = 1cd.1sr = 1cd

10

Light amount

lumen second

lm.s

Lumen second is the amount of light of a luminous flux of one lumen calculated in one second.

1lm.s = 1cd.s

lumen hour

lm.h

1lm.h = 3,600 lm.s

11

Luminous capacity

lumen per square meter

lm/m2

Lumen per square meter is the luminous capacity of a spherical source having a surface of 1 square meter in area, emitting a luminous flux of 1 lumen distributed evenly in all directions.

1lm/m2 = 1m-2.cd

12

Illuminance

lux

lx

The lux is the illuminance of a surface receiving a luminous flux of one lumen evenly distributed on an area of one square meter of that surface.

1lx = 1lm/1m2 = 1m-2.cd

13

Illuminating amount

lux second

lx.s

Lux second is the illuminating amount corresponding to the illuminance of 1 lux in 1 second.

1lx.s = 1m-2.s.cd

lux hour

lx.h

1lx.h = 3,600 lx.s

14

Focus (optical force)

reciprocal meter

m-1

The reciprocal meter is the focus of an optical system having a focal length of 1 meter in a refractive environment equal to 1.

1m-1 = 1m-1

diopter

dp

The diopter is another name of the reciprocal meter

1 dp = 1m-1

VI. Acoustic units

1

Frequency

hertz

Hz

1Hz = 1s-1

2

Frequency range

octa

octa

Octa is the range between two frequencies when the ratio between the higher frequency and the lower frequency is 2.

1 octa = lg2 (f2/f1) = lg22 = 1

3

Acoustic pressure

pascal

Pa

1Pa = 1N/1m2 = 1m-1.kg.s-2

4

Acoustic velocity

meter per

m/s

1m/s = 1m.s-1

second

5

Volume velocity

cubic meter per second

m3/s

Cubic meter per second is the periodic volume velocity in a homogeneous acoustic field at a cross-section of 1m2 of an acoustic conductor, on which the particle velocity is 1 meter per second.

1m3/s = 1m3.s-1

6

Acoustic energy density

joule per cubic meter

J/m3

Joule per cubic meter is the acoustic energy density in an acoustic field having an energy of 1 joule evenly distributed in a volume of 1 m3.

1J/m3 = 1N.1m/m3 = 1m-1.kg.s-2

7

Acoustic power

watt

W

1W = 1J/1s = 1m2.kg.s-3

8

Acoustic intensity

watt per square meter

W/m2

Watt per square meter is the acoustic intensity in a plane sound wave when it transmits an acoustic energy of 1 joule across a surface of 1 square meter in a second.

1W/m2 = 1kg.s-3

9

Acoustic impedance (acoustic resistance)

pascal second per cubic meter

Pa.s/m3

Pascal second per cubic meter is the acoustic impedance of an acoustic transmission tube, in which the negative sine pressure of 1 pascal at any cross-section causes a volume velocity having a value of 1 cubic meter per second at such cross-section point.

1Pa.s/m3 = 1m-4.kg.s-1

10

Mechanical impedance (mechanical resistance)

newton second per meter

N.s/m

Newton second per meter is the mechanical impedance of a mechanical system when a periodic force of one newton, at the place of the force, causes a fluctuating velocity of 1 meter per second.

1N.s/m = 1 kg.s-1

11

Level of acoustic pressure

bel

B

The bel is the level of acoustic pressure of a sound when the double decimal logarithm of the ratio between the pressure of such sound and a compared pressure of 2.10-5 Pa is 1.

decibel

dB

The decibel is the level of acoustic pressure of a sound when 20 times of the decimal logarithm of the ratio between the pressure of such sound and a compared pressure of 2.10-5 Pa is 1.

12

Level of loudness

phon

phon

The phon is the lovel of loudness of monochromatic sounds of 1 kilohertz in frequency and 1 decibel in acoustic pressure.

VII. Chemo-physical and physio-atomic units

1

Atomic mass

kilogram

kg

See explanations at Section 1, Part I.

unified atomic mass unit

u

The unified atomic mass unit is a mass equal to 1/12 of the mass of an atom of the nuclide 12C.

1u = (1.660 540 2 � 0.000 001 0) x 10-27 kg*

* CODATA Bulletin 63 (1986)

2

Molecular mass

kilogram

kg

See explanation in Section 1 above

unified atomic mass unit

u

The mass of a molecule is the total mass of atoms in such molecule.

3

Amount of substance

mole

mol

The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles (14th CGPM, 1971).

The base unit.

4

Molar concentration

mole per cubic meter

mol/m3

Molar concentration is the number of moles of a dissolvable substance divided by the volume of the solution.

mole per liter

mol/l, mol/L

5

Molar energy

joule per mole

J/mol

In the solution of two substances A and B, the molar energy of substance A is:

mA = (�G/�nA)T,p,nB

and the molar energy of substance B is:

mB = (�G/�nB) T,p,nA

In which mA and mB are the molar energies of substance A and substance B respectively; nA and nB are their respective quantities and G is function Gibbs.

1

Radioactivity (of radionuclide)

becquerel

Bq

The becquerel is the radioactivity of a source of radiation in which the quotient of the expected value of the number of spontaneous nuclear displacements or isomeric displacements and the duration of time during which these displacements occur advances to the limit of 1/s.

1Bq = 1s-1

2

Absorbed dose

Gray

Gy

The gray is the dose absorbed in a material quantity of 1 kilogram which receives an energy of 1 joule from ionizing radiations under constant energy flux conditions.

1Gy = 1J/kg = 1m2.s-2

3

Dose equivalent

sievert

Sv

The sievert is the equivalent dose in a tissue quantity of 1 kilogram which receives an energy of 1 joule from ionizing radiations with a quality factor value of 1 with regard to the assessment of the equivalent dose against the biological effects of charged particles which produce the absorbed dose and their energy flux is constant.

1Sv = 1J/kg = 1m2.s-2

4

Kerma

gray

Gy

The gray is a kerma in a material quality of 1 kilogram which receives a total initial kinetic energy of 1 joule freed by charged ionized particles under constant energy flux conditions.

1Gy = 1J/kg = 1m2.s-2

5

Exposure

Coulomb per kilogram

C/kg

Coulomb per kilogram is the exposure of the photonic ionizing radiation generated in 1 kilogram of air of ions of the same sign having a total charge of 1 coulomb when all electrons (positive and negative), freed by photons in the air, stop completely there and all of their energy flux remains in the air.

1C/kg = 1kg-1.s.A

Notes:

1. In the above table, the SI units are placed under unbroken line (---), other units under broken line (---).

2. The way of writing the names and symbols of units shall comply with the following principles:

a/ The name of a unit is written in lower-case letters, though it derives from a proper name. For example: meter, second, ampere, kelvin, pascal�

b/ Generally, the symbol of a unit is written in lower-case letters, except for cases where the unit name derives from a proper name, the first letter in the symbol is capitalized. For example: m, s, A, K, Pa�

c/ When a unit is formed by multiplying two or more units, the raised dot (in language systems having limited characters, a normal dot can be used) or a one-character space will be used to indicate this multiplication.

For example: The symbol of newton meter is N.m or Nm.

d/ When a unit is formed by one unit divided by another unit, a dash (�), a slash (/) or

a negative power will be used to indicate this division. For example: The symbol of meter per second is

m

�, or m/s or m.s-1 or ms-1

s

Particularly for cases where the slash is followed by a multiplying or dividing mark, such marks

must be put in blankets. For example: The symbol of joule per kilogram kelvin is J(kg.K), or

J

�� or J.kg-1.K-1.

kg.K

B. Decimal multiples and submultiples of SI units:

The names (or symbols) of the decimal multiples and submultiples of the SI units are formed by joining before the name (or symbol) or a SI unit one name (or symbol) in the table below:

Name

Symbol

Factor

multiples

yotta

Y

1 000 000 000 000 000 000 000 000 = 1024

zetta

Z

1 000 000 000 000 000 000 000 = 1021

exa

E

1 000 000 000 000 000 000 = 1018

peta

P

1 000 000 000 000 000 = 1015

tera

T

1 000 000 000 000 = 1012

giga

G

1 000 000 000 = 109

mega

M

1 000 000 = 106

kilo

k

1 000 = 103

hector

h

100 = 102

deca

da

10 = 10

submultiples

deci

d

0.1 = 10-1

centi

c

0.01 = 10-2

mili

m

0.001 = 10-3

micro

m

0.000 001 = 10-6

nano

n

0.000 000 001 = 10-9

pico

p

0.000 000 000 001 = 10-12

femto

f

0.000 000 000 000 001 = 10-15

atto

a

0.000 000 000 000 000 001 =10-18

zepto

z

0.000 000 000 000 000 000 001= 10-21

yocto

y

0.000 000 000 000 000 000 000 001 =10-24

Notes:

1. The name (or symbol) of a decimal multiple or submultiple comes right before the name (or symbol) of a unit (without a space). For example: milimeter (mm), kilometer (km).

Particularly for the name (or symbol) of a multiple or submultiple of a mass unit, it will be formed by placing before the name (or symbol) of the "gram" unit (or its symbol g) a name (or symbol) in the above table (1 g= 0.001 kg = 10-3 kg).

2. Not to join two names (or symbols) of the multiples or submultiples in the above table. For example: nanometer (nm) will be used for 10-9 , but not milimicrometer (mmm).

Appendix II

UNITS PERMITTED FOR USE FOR A DEFINITE TIME

(issued together with the Government�s Decree No. 65/2001/ND-CP of September 28, 2001)

Ordinal

Quantity

Unit

Description

Used still

number

Name

Symbol

1

weight

li

li

1 li = 0.037 5 g

31.12.2010

2

weight

carat

ct

1 ct = 0.2 g

31.12.2010

3

weight

luong

lg

1 lg = 37.5 g

31.12.2010

4

weight

dong can (tael)

dc

1 dc = 3.75 g

31.12.2010

5

weight

phan

phan

1 phan = 0.375 g

31.12.2010

6

plane angle (angel)

circle

r

1 r = 2P rad

31.12.2005

7

force

kilogram force(kilopond)

kgl (kG; kgf, kp)

1 kgl = 1 kG = 1 kgf = 1 kp = 9.806 65 J

31.12.2005

8

pressure

technical

atmosphere

at

1 at = 98.066.5 kPa

= 0.980 665 x 105 Pa

31.12.2005

9

pressure

torr

Torr (mmHg)

1 Torr = 133.322 Pa

31.12.2005

10

pressure

meter of water column

mH2O

1 mH2O = 9.806 65 kPa

= 9.806 65 x 103 Pa

31.12.2005

11

work, energy

kilogram force meter (kilopond meter)

kgl.m (kG.m; kgf.m.; kp.m)

1 kgl.m = 9.806 65 J

31.12.2005

12

calorie

calorie

cal

1 cal = 4.186 8 J

31.12.2005

13

radioactivity

curie

Ci

1 Ci = 37 GBq = 3.7 x 1010 Bq

31.12.2005

14

absorbed dose

rad

rad

1 rad = 0.01 Gy = 10-2 Gy

31.12.2005

15

exposure

roentgen

R

1 R = 0.258 mC/kg

= 2.58 x 10-4 C/kg

31.12.2005